On Thursday, Jack Teixeira, a 21-year-old Air National Guardsman, was arrested for his alleged involvement in leaking classified Pentagon documents, which caused embarrassment for the U.S. and its allies and raised concerns about Ukraine's ability to succeed in its war with Russia. The arrest came shortly after President Biden announced that the U.S. was close to identifying the source of the most extensive government records leak in a decade.

Teixeira was reportedly an Airman First Class with the 102nd Intelligence Wing of the Massachusetts Air National Guard and leader of the Discord server where the files were shared, according to The New York Times. It is uncertain how Teixeira had access to such highly classified information.

Attorney General Merrick Garland announced that Teixeira was suspected of "unauthorized removal, retention, and transmission of classified national defense information." The FBI arrested him without incident, and he will have an initial appearance in the U.S. District Court for the District of Massachusetts.

Pentagon press secretary Air Force Brig. Gen. Pat Ryder declined to comment on Teixeira or the Justice Department's investigation during a Thursday briefing. However, he stated that the leak was a "deliberate, criminal act" and emphasized the importance of adhering to the rules, regulations, and responsibilities associated with security clearances.

According to a report by The Washington Post, in 2020, a group of online friends who shared an interest in guns and military gear created a server on Discord called "Thug Shaker Central." The group's leader, known as "OG," worked at an unidentified military base and began sharing transcribed notes of classified intelligence with the server, which hosted up to 30 members.

The Post report did not name Teixeira, but a later New York Times report identified him as the group leader. OG claimed to spend part of his time in a secure government facility that prohibited cell phones and cameras. Over time, interest in the secrets dwindled, and OG started taking pictures of the classified documents to maintain the group's attention on government secrets.

The classified documents first appeared outside of Thug Shaker Central in early March, as reported by investigative group Bellingcat. The documents were never intended to leave the original server, according to The Times and The Post.

The New York Times' report on the classified Pentagon documents circulating online sparked global attention. The documents, now being shared on Telegram and Twitter, provided insider information on battlefield assessments in the war in Ukraine. The Pentagon is currently reviewing the document leaks, and defense officials are examining policies around information sharing.

Political science professor Michael Butler at Clark University said the document leaks exposed a possible "systemic weakness" and vulnerability in the Pentagon. Lawmakers from both parties are pushing the Pentagon for answers on how the leaks occurred and how to prevent them in the future.